CN108702080B - Switching device for a high voltage power system and arrangement comprising such a switching device - Google Patents
Switching device for a high voltage power system and arrangement comprising such a switching device Download PDFInfo
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- CN108702080B CN108702080B CN201680081031.1A CN201680081031A CN108702080B CN 108702080 B CN108702080 B CN 108702080B CN 201680081031 A CN201680081031 A CN 201680081031A CN 108702080 B CN108702080 B CN 108702080B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/54—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements of vacuum tubes
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/10—Modifications for increasing the maximum permissible switched voltage
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/52—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of gas-filled tubes
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
Abstract
The present invention relates to a switching device (24) for a high voltage power system and an apparatus comprising such a switching device. The switching device comprises a first semiconductor switching element (26) capable of being switched off and having a first gate (G1) and first and second current conducting terminals (CCT1, CCT2), and a second switching element (28) capable of being switched on and comprising a valve having a second gate (G2) and first and second electrodes (E1, E2). The switching elements (26, 28) are connected in series, wherein the first electrode (E1) is connected to the second current conducting terminal (CCT2), wherein the first current conducting terminal (CCT1) and the second electrode (E2) are provided to be connected to the power system, and the switching elements are jointly operable to break or form a current path between the second electrode (E2) and the first current conducting terminal (CCT 1).
Description
Technical Field
The present invention relates generally to high voltage power systems. More particularly, the present invention relates to a switching device for a high voltage power system and an apparatus comprising such a switching device.
Background
Switchgear is known for use in various high voltage applications. As an example, the switchgear may be used as part of or as a main circuit breaker for a hybrid Direct Current (DC) circuit breaker, which uses mechanical and electrical switches. The switching device may also be provided in a valve of a Voltage Source Converter (VSC). In this case, the VSC may convert between Alternating Current (AC) and DC, and may be provided in a converter station that is an interface between the DC high voltage power system and the AC high voltage power system. VSCs may also be provided as reactive power compensation devices in AC systems, such as Static VAR Compensators (SVCs). These are just a few examples of devices that may use HV switching apparatus.
The switching device in the above example needs to be able to withstand high voltages. Therefore, the switchgear must be able to avoid failure at sub-withstand voltages. Common to all these systems is that switching devices, such as Insulated Gate Bipolar Transistors (IGBTs) or Integrated Gate Commutated Thyristors (IGCTs), are now usually realized by using semiconductor switching elements. In high voltage applications, the switching element has a relatively low voltage blocking capability, typically in the range of several kV. Therefore, for very high voltage applications, such as in power grid systems, a series connection of these elements is required to reach several tens kV to several hundreds kV. This requires higher reliability of the individual devices, but also increases the complexity and size requirements of such devices.
It is well known that for lower voltage ranges, a combination of two different types of switching elements may be used to provide a higher withstand voltage for one device and a lower switching capability for the second device.
Some proposals have been made for providing combinations of different types of semiconductor switching elements in a switching device. Such a switching device is often referred to as a "cascode device" if these different types of switching elements are connected in series. Thus, a "cascode device" is a series-connected hybrid device, and the expression will be used in this sense hereinafter. The main reason for this approach is to combine certain advantageous features of each element to achieve better overall performance and trade-off relationships.
One such combination is known as a SiC Junction Field Effect Transistor (JFET) and a silicon Metal Oxide Semiconductor Field Effect Transistor (MOSFET) cascode, for example to replace an IGBT. This combination provides a normally off device because normally on JFETs are undesirable in many applications. Furthermore, MOSFET gate drive control is preferred in most applications where it is desirable to replace IGBTs with JFET cascodes.
Another example is a gate turn-off thyristor (GTO) or integrated Gate Commutated Thyristor (GCT), referred to as an emitter turn-off thyristor (ETO), in series with a MOSFET. This has been shown to provide a low on-state thyristor structure with voltage controlled gate drive and saturation/short capability. It is noted that the IGCT concept also employs a cascode structure, in which a MOSFET is connected in series with the IGCT gate. However, MOSFETs can only commutate off current compared to ETO.
But these examples of combining two types of semiconductor devices can only reach a withstand voltage below a few 10kV and are therefore not suitable for general HV applications, unless several of them are connected in series again.
Many high voltage power systems are used for power transmission. In these systems, it is important that efficiency is high. The power delivered to the power transmission system leaves the power transmission system as much as possible. Losses in the power transmission system must be low, in particular in order to reduce the heat caused by them.
However, a problem with series-connected semiconductor switching elements is that each such element has conduction losses. Therefore, the conduction loss of the switching device constituted by the semiconductor switching elements will be the sum of the conduction losses of the semiconductor switching elements. Thus, conduction losses of the switching device may have a significant impact on the efficiency of the high voltage power system. Further, if the respective devices are combined in series, the reliability of each device must be high. They are also more complex, for example, because each device requires the use of a gate cell for switching. Finally, the space requirements of these systems are rather high.
It is therefore intended to obtain a switching device in which a reduction in the conduction losses can be obtained, in particular by using a single device with a high voltage withstand capability and relatively low losses.
The present invention is provided to solve this problem. "valves", i.e. vacuum tubes and in particular gas-filled tubes, have been used before the widespread use of power semiconductor devices to provide a switching function in high-voltage applications. These tubes are based on electron flow in a plasma under vacuum or at low pressure. They have been shown to be able to withstand high voltages up to 135 kV. Thus, they have the potential to be used as a single device rather than a series connection of many devices.
There are a large number of designs of such tubes using different physical mechanisms to provide different functions. They can be equipped with high current and turn on and off functions. In particular, low pressure gas tubes have been developed for use in electrical applications.
Disclosure of Invention
The invention solves the problem of obtaining a switching device with low conduction losses and the possibility of using only two devices to provide a high voltage withstand capability.
According to a first aspect of the invention, the object is achieved by a switching device for a high voltage power system, the switching device comprising:
a first semiconductor switching element capable of being turned off and having a first gate, and first and second current conducting terminals, an
A second switching element capable of conduction and including an electron tube having a second gate, and first and second electrodes,
wherein the first switching element and the second switching element are connected in series with each other such that the first electrode of the second switching element is electrically connected to the second current conducting terminal of the first switching element, wherein the first current conducting terminal and the second electrode are provided for connection to an electrical power system, and the switching elements are jointly operable for disconnecting or forming a current path between the second electrode and the first current conducting terminal
According to a second aspect of the invention, the object is achieved by an arrangement in a high voltage power system comprising a switchgear according to the first aspect.
Jointly operable switching elements may require that they are operable sequentially in order to achieve a common goal of forming or breaking a current path.
The present invention has many advantages. The switching device has low conduction losses. Furthermore, the number of switching elements in the switching device is small, thereby reducing costs, size requirements and allowing high reliability.
Drawings
The invention will now be described with reference to the accompanying drawings, in which
Fig. 1 schematically shows a DC power transmission system connected to two AC systems, wherein the DC system comprises two voltage source converters and a hybrid DC breaker, and one of the AC systems comprises reactive power compensation means,
figure 2 schematically shows a first variant of the switching device according to the invention,
figure 3 schematically shows a second variant of the switching device according to the invention,
figure 4 schematically shows a third variant of the switching device according to the invention,
figure 5 schematically shows a fourth variant of the switching device according to the invention,
figure 6 schematically shows a first type of voltage source converter in which a switching device is used,
figure 7 shows a second type of voltage source converter comprising a plurality of cells,
FIG. 8 shows a cell in which the switching of the cell is realized by a switching device, an
Fig. 9 schematically shows a hybrid DC breaker comprising a main breaker implemented using at least one switching device.
Detailed Description
Hereinafter, a detailed description will be given of preferred embodiments of the present invention.
Fig. 1 shows a simplified Direct Current (DC) power transmission system comprising a first converter station 10 and a second converter station 12. The two converter stations 10 and 12 are interconnected by a DC link 18, the DC link 18 comprising a hybrid HVDC breaker 22 using both mechanical and electrical switches. The first converter station 10 comprises a first converter 14 connected to an Alternating Current (AC) power transmission system via a first transformer T1, and the second converter station 12 comprises a second converter 16 connected to a second AC power transmission system via a second transformer T2. Any AC power transmission system is not shown in detail. However, in the first AC power transmission system a reactive power compensation device 20 is provided, which may be a so-called Static VAR Compensator (SVC). Both the DC system and the AC system are examples of a high-voltage power system, and in this case, also an example of a high-voltage power transmission system.
Both the converter 14 and the converter 16 may be a Voltage Source Converter (VSC) and may be a two-level converter or a multi-level converter comprising a plurality of cells, i.e. a voltage source converter employing a plurality of cells for forming a plurality of voltage levels. The conversion in this example is also between DC and three-phase AC. Thus, both converters have three legs, one leg for each phase. In the examples given later, only one bridge arm will be shown and described. However, it is well known that all legs have the same implementation. It should also be realised that there are other types of voltage source converters, such as neutral point clamped three level converters and various n level converters.
The converter 14 and 16, the reactive power compensation device 20 and the hybrid DC breaker 22 are all examples of devices in a high voltage power system using switchgear. It should be appreciated that these are just a few examples of configurations in a high voltage power system, such as a power transmission system in which a switchgear may be used.
As mentioned before, the conventional way of providing a switching device is by connecting a large number of semiconductor switching elements in series, i.e. switching elements realized by using semiconductor devices such as Insulated Gate Bipolar Transistors (IGBTs) or Integrated Gate Commutated Thyristors (IGCTs).
As also previously mentioned, the use of several such elements in series increases the conduction losses of the resulting switchgear, which in many cases has a negative effect on the efficiency of the high voltage power system in which the switchgear is used.
It may also increase the likelihood of switchgear failure and the cost and size of the switchgear.
The above problems are solved by introducing a new switching device.
The novel switching device is a "cascode arrangement" comprising a series connection of two different switching elements, a semiconductor switching element and a valve-based switching element (such as a gas-filled or vacuum tube with a very high voltage blocking capability).
Fig. 2 shows a first variant of the new switching device 24. The switching device 24 comprises a first semiconductor switching element 26, the first semiconductor switching element 26 being at least capable of being turned off and possibly also capable of being turned on and having a first gate G1, and a first current conducting terminal CCT1 and a second current conducting terminal CCT 2.
The switching device 24 further comprises a second switching element 28, the second switching element 28 being at least capable of conducting and possibly also capable of being switched off, and comprising a valve having a second gate G2, and a first electrode E1 and a second electrode E2, wherein the gate G2 may be configured to control a current, advantageously a unidirectional current, between the electrodes E1 and E2. The first electrode E1 is a cathode, and the second electrode E2 is an anode.
As can be seen in fig. 2, the first switching element 26 and the second switching element 28 are connected in series with each other such that the first electrode E1 of the second switching element 28 is electrically connected to the second current conduction terminal CCT2 of the first switching element 26. Here, the second electrode E2 and the first current conducting terminal CCT1 are connection terminals of the switching device 24, which means that they are provided for connection to other parts of the high voltage power system. If the switchgear 24 is part of a device, such as the converter 14, the SVC20, or the DC breaker 22, the terminals CCT1 and E2 may be connected to the converter 14, the SVC20, or other parts of the DC breaker 22.
The second switching element 28 may be a gas-filled tube. Alternatively, it may be a vacuum tube. The first switching element 26 may be a thyristor-based switching element, such as an integrated gate commutated thyristor (GTO, IGCT). Alternatively, it can also be a transistor, for example an Insulated Gate Bipolar Transistor (IGBT) or a junction field effect transistor JFET. In the case of an IGCT, the first current-conducting terminal CCT1 may be a cathode and the second current-conducting terminal CCT2 may be an anode. In the case of an IGBT, the first current conducting terminal CCT1 may be an emitter and the second current conductor terminal CCT2 may be a collector.
The switching device 24 may be a very high voltage gas-vacuum tube element or a hard-vacuum tube element as the second switching element in series with a relatively lower voltage semiconductor element as the first switching element. As second switching element, there are many options based on different concepts, such as hard vacuum tubes (like triodes, tetrodes, etc.), gas filled tubes (like Thyratrons, cross-field plasma discharge switches), or specific elements like crossscan and hollow electrode elements (like hollowron or pseudo-spark switches), to name a few. These elements have a wide range of voltage and current ratings and different functions. However, they differ from power semiconductor devices mainly in their very high voltage withstand capability for a single device (which may be between 10kV-135 kV), thus making them suitable for very high voltage systems such as HVDC. Some of these elements also have a very attractive loss behaviour for such high voltage arrangements compared to an equivalent series-connected power element configuration for achieving the same rated voltage. They also provide turn-on only functionality, such as Thyratron, or turn-on and turn-off functionality, such as crosstron and Hollowtron, depending on the element type.
Only the second switching element may be able to conduct. On the other hand, the first switching element requires at least off control. This means that if the second switching element has a gate that is capable of conducting, the first switching element 26 may not have the capability of conducting, but only a switching element of the off type, such as a JFET.
Furthermore, the first switching element 26 has a first voltage withstand capability, while the second switching element 28 has a second voltage withstand capability, and the voltage withstand capability of the second switching element 28 may be significantly higher than the voltage withstand capability of the first switching element 26. For example, it may be ten times the voltage withstand capability of the first switching element. Alternatively, it may be at least 20 times higher or at least 25 times higher.
Such a combination may be, for example, an IGCT capable of withstanding 4500V connected in series to a Crossatron or Thyratron capable of withstanding up to 135 kV. It can be seen that this will result in 80/3 times higher second voltage withstand than first voltage withstand.
It can also be seen in fig. 2 that the second electrode E2 has a higher potential than the first current conducting terminal CCT1, which is illustrated by the second electrode having a positive potential (+) and the first current conducting terminal having a negative potential (-). This means that the technical or conventional current is from the second electrode E2 to the first current conducting terminal CCT 1. The electron flow will be in the opposite direction.
Further, the switching elements may be jointly operable for breaking or forming a current path between the second electrode E2 and the first current conducting terminal CCT 1. In the example shown in fig. 2, the combined operation is obtained using a gate control unit 30 as part of the switching device 24. Thus, the combined operation is a cooperative operation. The join operation may also be a sequential operation. It should be realized, however, that such a joint operation is not necessarily obtained by such a gate control unit 30, but may be provided as part of the control of the apparatus comprising the switching device 24. For example, if the switching device 24 is provided as part of a VSC (such as the first converter 14), the gate control function may be provided as part of the overall control of the switching devices of the VSC (e.g. for use in forming part of the AC waveform).
The gate control unit 30 is provided for forming or breaking a current conduction path between the second electrode E2 and the first current conduction terminal CCT 1.
The gate control unit 30 may be configured to form a current path by using a gate control sequence including: the gate control signal is first applied to the first gate G1 to turn on the first switching element 26, and then applied to the second gate to turn on the second switching element 28. Accordingly, the second gate G2 may receive the gate control signal after the first switching element 26 is turned on. The order may also be reversed.
Thus, the semiconductor switching element 26 and the gate diode element 28 may initially be turned on in a given sequence, which is not critical as long as the power semiconductor device 26 is turned on first and the tube 28 still blocks the voltage. Thus, it is critical to turn on the valve, while the turn on of the semiconductor device may be optional.
One limitation of most types of lamps used as second switching elements is that they can typically only switch off moderate (normal) currents, since they rely on low plasma density in the process. In contrast, the semiconductor element can switch off a relatively high current.
To address this problem, the gate control unit 30 may first apply a gate control signal to the first gate G1 to turn off the first switching element 26 when opening the current path, thereby reducing the current in the current path from a first regular current level to a second lower off current level in order to cause the second switching element 28 to turn off at this second current level to open the current path.
Depending on the type of the second switching element 28, the gate control unit 30 may also apply a gate control signal to the second gate G2 to switch the second switching element 28 off to open the current path when the current in the current path is at the second current level.
In the examples of IGCT and crosstron or Thyratron given above, during turn-off, IGCT is first turned off to reduce the current to a very low level before turning off gas tube 28 (in the case of crosstron). If the second switching element 28 is a Thyratron, the gate control signal may not be needed because the Thyratron may turn off by itself due to the low current flow.
It can be seen that the use of the first switching element 26 also allows to provide the second switching element 28 with a turn-off capability, the second switching element 28 not normally providing its turn-off capability, or alternatively strongly enhancing their turn-off capability for higher nominal currents. Furthermore, the first switching element 26 improves the reliability of the combined device.
The additional voltage drop across the semiconductor is always only a small factor compared to the usual forward voltage of the tube of 10V up to 1kV, which strongly depends on the chosen tube design.
In principle, the configuration of the two switching elements in the cascode device may be arbitrary. It is thus alternatively possible that the first electrode E1 of the second switching element 28 is connected to a negative potential (-) and the second electrode E2 is electrically connected to the first current conducting terminal CCT1 of the first switching element 26 and the second current conducting terminal CCT2 of the first switching element 26 is connected to a positive potential (+). A second variant of the invention, showing this implementation but without the control unit, is schematically shown in fig. 3. Thus, there will be a current flow from the second current conducting terminal CCT2 to the first electrode E1. However, it may be preferred to have the electron tube first in the technical current flow direction and then the semiconductor device, just as shown in fig. 2. Thus, the switching device 24 may be designed for connection to a high voltage power system such that the current conduction direction therethrough is from the second electrode E2 to the first current conduction terminal CCT 1. This is due to the asymmetric design of the tube, where the switching on (and off) is due to the voltage relative to the cathode. Generally, electron tubes have a high withstand voltage between the grid and the anode, and a low voltage is required between the grid and the cathode for their control. In this configuration, both gate G1 and gate G2 need to be controlled relative to the "-" voltage in fig. 2. In contrast to the two devices exchanged, G2 would be controlled with respect to the "-" voltage, but G1 would be controlled with respect to the intermediate voltage level. During the on state, the voltage between G1 and G2 will be of the order of the high voltage.
In addition, some gas tube elements typically require that most of the current be diverted to the grid by using an additional power source. In the configuration shown in fig. 2, the semiconductor element is allowed to limit the commutation current, since it is part of the current path. This is not the case in alternative configurations where the positions of the semiconductor device and the gas-filled tube are swapped, which reduces the usefulness of the design.
As described above, the switching device 24 may be used in various apparatuses, such as in VSCs. In such devices, anti-parallel current regulating elements, such as diodes, are typically used. Thus, the switching device 24 may comprise an anti-parallel diode. One example of this is shown in fig. 4, which fig. 4 shows the first switching element 26 and the second switching element 28 from fig. 2. However, there is also here an anti-parallel diode D, the cathode of which is connected to the second electrode E2 and the anode of which is connected to the first current conducting terminal CCT 1. Please remember that in this case the diode can be based on the semiconductor or valve principle. In this modification, the gate control unit is omitted. However, it is also possible to include a gate control unit here.
Another example of a switching device including anti-parallel unidirectional current conducting elements is shown in fig. 5. Fig. 5 also shows the first switching element 26 and the second switching element 28 from fig. 2. However, here again in the arrangement 24 there is a unidirectional current conducting element comprising an anti-parallel sealed valve 31, the anti-parallel sealed valve 31 comprising a third gate G3, and a third electrode E3 and a fourth electrode E4, wherein the gate G3 is configured to control the current between the electrodes E3 and E4, i.e. a unidirectional current. The third electrode E3 may be an anode, and the fourth electrode E4 may be a cathode. The third electrode E3 is connected to the first current conducting terminal CCT1, and the fourth electrode E4 is connected to the second electrode E2. Furthermore, a gate control unit may of course be added here, so that the gate control unit may also control the third gate G3 to be, for example, always on.
As mentioned above, the switching device 24 may be used in many types of apparatuses. Fig. 6 shows the leg of the first converter, which is realized as a two-level converter 14A with two converter valves CV1 and CV2, wherein the first converter valve CV1 is connected between the first transformer T1 and the negative DC voltage-V of the DC link 18DCAnd a second converter valve CV2 is connected between the first transformer T1 and the positive DC voltage + V of the DC link 18DCIn the meantime. There is also a DC link capacitor C connected across the two valves CV1 and CV 2. In this arrangement, each valve may be implemented by a switching device such as that shown in fig. 2 and 3. If a second valve CV2 is provided, the second electrode will be connected to a positive DC voltage + VDCAnd the first current conducting terminal would be connected to the first transformer T1. If the switching device of fig. 2 or fig. 3 is to be used, it may be necessary to add anti-parallel unidirectional current conducting elements as shown in fig. 4 and fig. 5. Alternatively, the switching device of fig. 4 and 5 may be used directly.
Another example of an apparatus that may use the switching device 24 is shown in fig. 7. In this case the first converter is a modular multilevel converter 14B using half bridge cells, where fig. 7 shows a first leg comprising an upper leg and a lower leg joined (join) to a leg midpoint via corresponding leg reactors LA and LB, respectively, where the leg midpoint is joined to a first transformer (not shown). As shown in fig. 7, each leg consists of a plurality of cells 32, each cell 32 being implemented as a series connection of two switches in parallel with a cell capacitor. As also shown in fig. 7, such switches are typically implemented as IGBTs with anti-parallel diodes.
As shown in fig. 8, each switch of the unit 32' may be replaced by a switching device 24, such as the switching device of fig. 4 or 5. Thereby, the two switching devices 24 and the cell capacitor C are connected in seriesUnit cellAre connected in parallel. In this case, the second electrode of the upper switching device will be connected to the cell capacitor CUnit cellAnd a first current-conducting terminal thereof will be connected to the lower switching device, and more particularly to the second electrode of the lower switching device, and a second current-conducting terminal thereof will be connected to the cell capacitor CUnit cellThe lower end of (a).
If the switching device of fig. 2 or fig. 3 is used instead, the corresponding unidirectional current conducting element must of course be connected in parallel with each switching device 24 as shown in fig. 4 and fig. 5.
The SVC can also be implemented as a VSC, e.g. by a modular multilevel VSC, where three legs are connected in a delta configuration. In this case, each leg can be realized by one or more switching devices.
Finally, a hybrid HVDC breaker 22 is shown in fig. 9. It comprises a main breaker 35 and a load changeover switch 38, the main breaker 35 being connected in series with an ultra high speed disconnector (disconnector)36, for example realized by means of a mechanical switch. There is also a first surge arrester (arrestor) SA1 in parallel with the main breaker 35 and a second surge arrester SA2 in parallel with the load reversing switch 38.
In this case, the main breaker 35 may be implemented by one or more series-connected switching devices. The load reversing switch may also employ a switching device.
In case the AC system has an AC circuit breaker, which is usually realized by series-connected semiconductor switching elements, then such semiconductor switching elements may also be replaced by switching elements.
A new switchgear has thus been shown which can be used in many different devices in a high voltage power system, such as a high voltage power transmission system. The new switching device has many advantages including low conduction losses, can be realized with a limited number of components, and has high reliability.
The gate control unit may be implemented in the form of discrete components, such as a combination of logic circuits. Programmable circuits such as Field Programmable Gate Arrays (FPGAs) or Application Specific Integrated Circuits (ASICs) may also be used. Yet another alternative is in the form of a processor with accompanying program memory comprising computer program code to perform the required control functions when run on the processor.
It will be obvious from the foregoing discussion that the invention may be varied in many ways. It is therefore to be understood that the invention is not to be limited except as by the appended claims.
Claims (20)
1. A switching device (24) for a high voltage power system, the switching device comprising:
a first switching element (26) capable of being turned off and having a first gate (G1) and first (CCT1) and second (CCT2) current conducting terminals, and
a second switching element (28) which is capable of conducting and comprises an electron tube having a second gate (G2) and a first electrode (E1) and a second electrode (E2),
wherein
The first switching element (26) and the second switching element (28) are connected in series with each other such that the first electrode (E1) of the second switching element (28) is electrically connected to the second current conducting terminal (CCT2) of the first switching element (26),
the first current conducting terminal (CCT1) and the second electrode (E2) are provided for connection to the power system,
the switching elements are jointly operable for opening or forming a current path between the second electrode (E2) and the first current conducting terminal (CCT1), and
the first gate (G1) is operable to receive a gate control signal for turning off the first switching element (26) for reducing the current in the current path from a normal first current level to a lower off second current level so as to allow the second switching element (28) to be turned off at this second current level to open the current path.
2. The switching device (24) of claim 1, wherein the first switching element (26) has a first voltage-withstanding capability, the second switching element (28) has a second voltage-withstanding capability, and the voltage-withstanding capability of the second switching element (28) is at least ten times higher than the voltage-withstanding capability of the first switching element (26).
3. The switching device (24) according to claim 1 or 2, designed for connection to the high voltage power system such that a current conducting direction through the switching device is from the second electrode (E2) to the first current conducting terminal (CCT 1).
4. The switching device (24) according to claim 1 or 2, wherein the second switching element (28) is operable to be turned off by the second gate (G2) being operable to be turned off, and the second gate (G2) is operable to receive a gate control signal for turning off the second switching element (28) in order to open the current path, when the current in the current path is at the second current level.
5. The switching device (24) of claim 1 or 2, wherein the first switching element is operable to be turned on by the first gate (G1) being able to be turned on.
6. The switching device (24) of claim 5, wherein the first gate (G1) is operable to receive a gate control signal for turning the first switching element (26) on, and the second gate (G2) is operable to receive a gate control signal for turning the second switching element (28) on after the first switching element (26) is turned on.
7. The switching device (24) according to claim 4, further comprising a gate control unit (30) for applying at least one gate control signal to the first gate (G1).
8. The switching device (24) according to claim 1 or 2, further comprising a unidirectional conducting element connected in parallel with the first switching element (26) and the second switching element (28).
9. The switching device (24) of claim 8 wherein the unidirectional conducting element is a diode D.
10. The switching device (24) of claim 8, wherein the unidirectional conductive element (31) comprises a valve having a third gate (G3) and third and fourth electrodes (E3, E4), wherein the third gate (G3) is configured to control a current between the third and fourth electrodes (E3, E4).
11. The switching device (24) according to claim 1 or 2, wherein the electron tube of the second switching element (28) is a gas tube.
12. The switching device (24) according to claim 1 or 2, wherein the valve of the second switching element (28) is a vacuum tube.
13. The switching device (24) according to claim 1 or 2, wherein the first switching element (26) is a thyristor-based switching element, such as an integrated gate commutated thyristor.
14. The switching device (24) according to claim 1 or 2, wherein the first switching element (26) is a transistor.
15. The switching device (24) of claim 14, wherein the transistor is an insulated gate bipolar transistor or a junction field effect transistor.
16. An arrangement (14A, 14B, 20, 22) in a high voltage power system comprising a switching device (24) according to any of the preceding claims.
17. The device of claim 16, wherein the device is a hybrid DC breaker (22).
18. The arrangement of claim 17, wherein the switching device (24) is comprised in a main breaker (35) of the hybrid DC breaker (22).
19. The apparatus of claim 16, wherein the apparatus is a voltage source converter (14A) and the switching device is a valve (CV1) in the voltage source converter (14A).
20. The apparatus of claim 16, wherein the apparatus is a modular multilevel converter (14B) and the switching devices (24) are switches of cells (32') in the modular multilevel converter (14B).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2016/052595 WO2017137057A1 (en) | 2016-02-08 | 2016-02-08 | Switching device for a high voltage power system and an arrangement comprising such a switching device |
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| CN108702080A CN108702080A (en) | 2018-10-23 |
| CN108702080B true CN108702080B (en) | 2021-01-12 |
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| CN201680081031.1A Active CN108702080B (en) | 2016-02-08 | 2016-02-08 | Switching device for a high voltage power system and arrangement comprising such a switching device |
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| WO (1) | WO2017137057A1 (en) |
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| EP3747100B1 (en) * | 2018-01-30 | 2022-03-16 | Hitachi Energy Switzerland AG | Surge arrestor dimensioning in a dc power transmission system |
| US11251598B2 (en) | 2020-01-10 | 2022-02-15 | General Electric Technology Gmbh | Gas discharge tube DC circuit breaker |
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| JPH08308094A (en) * | 1995-04-27 | 1996-11-22 | Sony Tektronix Corp | Circuit breaker apparatus |
| CN101632214A (en) * | 2007-02-06 | 2010-01-20 | 株式会社东芝 | Semiconductor switch and power converter to which the semiconductor switch is applied |
| CN104283448A (en) * | 2013-07-01 | 2015-01-14 | 株式会社日立制作所 | Power conversion device |
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| US5107292A (en) * | 1990-04-13 | 1992-04-21 | West Electric Co., Ltd. | Electronic flash unit |
| US8614904B2 (en) * | 2008-03-20 | 2013-12-24 | Abb Research Ltd. | Voltage source converter with switching cell bypass arrangement |
| CN104113229B (en) * | 2009-12-24 | 2017-01-11 | 三菱电机株式会社 | Power converter device and driving method thereof |
| GB2481602B (en) * | 2010-06-30 | 2017-11-15 | E2V Tech (Uk) Ltd | Switching arrangement |
| JP5676961B2 (en) * | 2010-07-30 | 2015-02-25 | スパンション エルエルシー | Power supply control circuit, electronic device, and power supply control method |
| US9716425B2 (en) * | 2013-01-21 | 2017-07-25 | Abb Schweiz Ag | Multilevel converter with hybrid full-bridge cells |
| CN104038085B (en) * | 2013-03-08 | 2016-07-06 | 台达电子工业股份有限公司 | Three-level current transformer |
| JP5867472B2 (en) * | 2013-09-17 | 2016-02-24 | 株式会社安川電機 | Power converter |
| EP2894776B1 (en) * | 2014-01-09 | 2017-11-29 | Dialog Semiconductor (UK) Limited | High voltage DC/DC Converter with master/slave buck output stages |
| US9397657B1 (en) * | 2014-07-24 | 2016-07-19 | Eaton Corporation | Methods and systems for operating hybrid power devices using multiple current-dependent switching patterns |
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2016
- 2016-02-08 CN CN201680081031.1A patent/CN108702080B/en active Active
- 2016-02-08 WO PCT/EP2016/052595 patent/WO2017137057A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08308094A (en) * | 1995-04-27 | 1996-11-22 | Sony Tektronix Corp | Circuit breaker apparatus |
| CN101632214A (en) * | 2007-02-06 | 2010-01-20 | 株式会社东芝 | Semiconductor switch and power converter to which the semiconductor switch is applied |
| CN104283448A (en) * | 2013-07-01 | 2015-01-14 | 株式会社日立制作所 | Power conversion device |
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| WO2017137057A1 (en) | 2017-08-17 |
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